Resistance exercise devices allow a user to exercise by providing a resistance to the movement of a user's arms, legs, or torso. Resistance is normally provided by working one muscle against another, or against gravity, and may include elastic bands to provide an increased resistance force. The usefulness of these devices depends, in part, on the ease with which a user can perform different types of exercises, the range or number of exercises that can be performed with the device, and the ease with which different users can adjust the device according to their height, weight, strength, and/or physical limitations.
Resistance exercise devices having elastic bands typically restrict the motion of a user's arms and/or legs, or the motion between the user and a support structure. Elastic exercise devices can be small, even portable, but have limited usefulness that result from their resistance characteristics, which depend on the length and elasticity of the elastic band. As a result of these characteristics, the elastic bands are useful for a specific length range, thus restricting the diversity of exercises for which it can be used. In addition, it may not be possible for different users to use the same device for the same exercise due to differences in height, weight, or strength between different users. Thus, for an elastic device to be generally useful, such as to provide a complete workout or to allow for different users, a plurality of elastic bands are required that must be easily interchangeable. No known prior art device provides the ease of use necessary to be generally useful across a wide range of exercises.
Another limitation of elastic resistance exercise devices is that the resistance is inconsistent and increases with increasing displacement, and also tends to snap back when the user decreases his or her effort. While this resistance response provides for a compact design, it is problematic as it does not recreate the resistance encountered by muscles during more natural types of exercising, such as running, swimming, etc. Yet another limitation of elastic devices is the inability to support a wide range of weight of the user—typically the devices are adapted to support only the resistance provided by the user's muscles. This creates extreme limitations in the exercises that can be performed by any individual elastic device. For this reason, elastic devices must be used over a limited range of stances, further limiting the user's workout.
Another type of resistance exercise device provides an inelastic strap that is attachable to a fixed location such as, for example, a door. These devices may overcome some of the limitations of the elastic devices previously discussed by providing inelastic straps that can be anchored between a door and a doorjamb. One of these devices has a fixed length strap attached to a door through a pulley system that allows the user to exercise by moving the arms in opposite directions. Another of these devices has a pair of fixed length straps anchored to a door. Both of these devices are of limited usefulness because of their fixed length and the range of exercises for which they can be used.
There is a need to provide a resistance exercise device that is easily adjustable so that it can provide a complete workout for any user, including adjustments that allow a wide range of stances and exercises, and that provides resistance to the user's motion in a form that is useful for exercising. In addition, there is a need to provide such a device that is adaptable to be easily portable to enable the device to be mounted to different locations for exercising.